<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script>
        var a = '[a, b, c, d]';
        var b = [1, 2, 3, 4];
        // write your code here...
        if(Array.isArray(a)==false)console.log("A不是数组");else console.log("A是数组");
        if(Array.isArray(b)==false)console.log("B不是数组");else console.log("B是数组");
    </script>
</head>
<body>

</body>
</html>